*, :before, :after
    margin: 0
    padding: 0
    border: none
    box-sizing: border-box
body
    font-size: 16px
    height: 100vh
a, input, button
    text-decoration: none
    &:focus
        outline: none
ol, ul
    list-style: none
h1, h2, h3
    font-size: inherit //继承父级的文字大小
    font-weight: normal
